For a long time I played exclusively d4 type of schemes (sometimes starting Nf3 or c4), trying to leverage a relatively narrow repertoire.
At some point (possibly out of boredom), I had an epiphany: I'm a lousy amateur that likes chess, why should I leave out from my chess experience the half of it that starts with 1. e4?
Ultimately, I believe a player like me rated about 2000 can (and should) play almost any opening as either Black or White with minimal preparation. Many years of following top chess tournaments (and few books) apparently gave me enough patterns to play almost anything.
After almost a couple of years into this experiment, the results (and ratings) have not been impacted negatively... and I had a lot of fun, especially in some wild lines against the Najdorf (think of Bg5 f4 Qd2 and a piece sacrifice in b5/d5/e6). Some opening disaster also, but I cant really say they never happened before